Spectrum control systems and methods are implemented to minimize power spectral density (PSD) offsets by adjusting gain of optical amplifiers in an optical section. The optical section is a logical boundary from one optical signal access point to a next adjacent optical signal access point. The systems and methods include estimating PSD offset from a given target for a peak channel at each span in the optical section, wherein the estimated PSD offset is divided at each span into two components including a self-introduced offset and an uncompensated offset from upstream; generating, for each span, a separate controller response for the self-introduced offset and the uncompensated offset from upstream; and controlling the gain of the optical amplifiers based on the separate controller response for the self-introduced offset and the uncompensated offset from upstream, for each span.